Impaired antipneumococcal antibody production in patients without spleens

Preserved splenic function after angioembolisation of high grade injury

BACKGROUND

After introducing splenic artery embolisation (SAE) in the institutional treatment protocol for splenic injury, we wanted to evaluate the effects of SAE on splenic function and assess the need for immunisation in SAE treated patients.

METHODS

15 SAE patients and 14 splenectomised (SPL) patients were included and 29 healthy blood donors volunteered as controls. Clinical examination, medical history, general blood counts, immunoglobulin quantifications and flowcytometric analysis of lymphocyte phenotypes were performed. Peripheral blood smears from all patients and controls were examined for Howell-Jolly (H-J) bodies. Abdominal doppler, gray scale and contrast enhanced ultrasound (CEUS) were performed on all the SAE patients.

RESULTS

Leukocyte and platelet counts were elevated in both SAE and SPL individuals compared to controls. The proportion of memory B-lymphocytes did not differ significantly from controls in either group. In the SAE group total IgA, IgM and IgG levels as well as pneumococcal serotype specific IgG and IgM antibody levels did not differ from the control group. In the SPL group total IgA and IgG Pneumovax(®) (PPV23) antibody levels were significantly increased, and 5 of 12 pneumococcal serotype specific IgGs and IgMs were significantly elevated. H-J bodies were only detected in the SPL group. CEUS confirmed normal sized and well perfused spleens in all SAE patients.

CONCLUSION

In our study non-operative management (NOM) of high grade splenic injuries including SAE, was followed by an increase in total leukocyte and platelet counts. Normal levels of immunoglobulins and memory B cells, absence of H-J bodies and preserved splenic size and intraparenchymal blood flow suggest that SAE has only minor impact on splenic function and that immunisation probably is unnecessary.

Does splenic preservation treatment (embolization, splenorrhaphy, and partial splenectomy) improve immunologic function and long-term prognosis after splenic injury?

BACKGROUND

: To assess the immunologic alteration and long-term prognosis after splenic injury from preservation treatment (PT) (embolization, splenorrhaphy, partial splencetomy) and to compare with splenectomy (SN).

METHODS

: The long-term prognosis of patients with blunt splenic injury treated at seven tertiary emergency centers in Japan was retrospectively studied. Patients were followed up by telephone interview and written questionnaire. Blood samples and abdominal computer tomography scans were taken from patients who consented, and immunologic indices and the remaining volume of the spleen were measured.

RESULTS

: There was no episode of severe infection requiring hospitalization among the 66 SN patients (760 patient-year) and the 34 PT (213 patient-year) patients. Blood tests from 58 patients (24 SN vs. 34 PT) revealed significant differences in platelet count, Howell-Jolly body positive rate (SN 87% vs. PT 3%), white blood cells, total lymphocyte count, T-cell count, B-cell count, and serum IgG level. There was no significant difference in serum levels of IgM or specific IgG antibodies against 14 types of Streptococcus pneumoniae capsular polysaccharide, C3, C4, high-sensitivity C-reactive protein, and B -cell subset (surface marker immunoglobulins: IgA, IgG, and IgM). Most patients had anti-S. pneumoniae antibody levels less than that of the reference level for multiple serotypes (average 3 in SN and 4 in PT). A computer tomography scan was taken from 33 PT patients; the volume of spleen remaining averaged 130 mL (range, 48-287 mL).

CONCLUSION

: PT did not show discernible advantage over SN in immunologic indices including IgM and 14 serotypes of anti-S. pneumoniae antibodies, suggesting prophylactic measures and close follow-up are necessary after PT and SN.

The C-type lectin SIGN-R1 mediates uptake of the capsular polysaccharide of Streptococcus pneumoniae in the marginal zone of mouse spleen

SIGN-R1, a recently discovered C-type lectin expressed at high levels on macrophages within the marginal zone of the spleen, mediates the uptake of dextran polysaccharides by these phagocytes. We now find that encapsulated Streptococcus pneumoniae are rapidly cleared by these macrophages from the bloodstream, and that capture also takes place when different cell lines express SIGN-R1 after transfection. To assess the role of the capsular polysaccharide of S. pneumoniae (CPS) in the interaction of SIGN-R1 with pneumococci, we first studied binding and uptake of serotype 14 CPS in transfected cells. Binding was observed and was of a much higher avidity (3000-fold) for CPS 14 than dextran. The CPSs from four different serotypes were also cleared by marginal zone macrophages in vivo. To establish a role for SIGN-R1 in this uptake, we selectively down-regulated expression of the lectin by pretreatment of the mice with SIGN-R1 antibodies, including a newly generated hamster monoclonal called 22D1. For several days after this transient knockout, the marginal zone macrophages were unable to take up either CPSs or dextrans. Therefore, marginal zone macrophages in mice have a receptor that interacts with capsular pneumococcal polysaccharides, setting the stage for further studies of the functional consequences of this interaction.

Invasive pneumococcal disease in the immunocompromised host

A normal constituent of the human upper respiratory flora, Streptococcus pneumoniae also produces respiratory tract infections that progress to invasive disease at high rates in specific risk groups. The individual factors that contribute to the development of invasive pneumococcal disease in this distinct minority of persons, include immune (both specific and innate), genetic, and environmental elements. Specific defects in host responses may involve age, deficiencies in levels of antibodies and complement factors, and splenic dysfunction. Combinations of these immune defects contribute to the increased rates of invasive pneumococcal disease in patients with sickle cell disease, nephrotic syndrome, neoplasms, and underlying medical conditions such as diabetes and alcoholic liver disease. The number of risk factors are greatest and the rates of invasive disease are highest in patients with HIV-1 infection, which has emerged as a major risk factor for serious S. pneumoniae infection worldwide.

Overwhelming postsplenectomy infection

The incidence of overwhelming sepsis in asplenic patients is low. It carries, however, an unacceptably high morbidity rate and mortality rate. The risk of development is related to the age of the patient as well as the duration since and the reason for splenectomy. It may also occur in functionally hyposplenic states. The rapidly lethal clinical course demands intense efforts toward prevention by both physician and patient, rapid recognition within the initial medical setting, and aggressive intervention with broad-spectrum antibiotics and other supportive measures.

Durable complete remission of macroglobulinemia after splenectomy: a report of two cases and review of the literature

Two patients with macroglobulinemia (monoclonal IgM in the serum) and massive splenomegaly were incapacitated by progressive disease refractory to standard chemotherapy. In each case, palliative splenectomy was followed by a prompt, complete, and unexpected clinical remission with disappearance from the serum of the monoclonal IgM component. One patient remains free of disease 12 years after splenectomy. The other patient remained free of detectable macroglobulinemia for 13 years after splenectomy. A review of the literature revealed other cases of remission of macroglobulinemia attributable to splenectomy alone. Data in humans and animals suggest that the spleen may facilitate IgM secretion by normal and malignant B lymphocytes. Splenectomy should be considered a possible treatment option for patients with massive splenomegaly and macroglobulinemia who progress on chemotherapy.

"How safe is splenectomy?"

The increased risk of sepsis in patients following splenectomy has been well documented. Fear of overwhelming post-splenectomy sepsis (OPSI) has resulted in a generalized trend towards splenic salvage among surgeons. However, splenorrhaphy and attempts at splenic salvage may of themselves predispose to significant morbidity, sometimes more serious than increased susceptibility to infection associated with splenectomy. This study aims to assess the risk of splenectomy and subsequent asplenia. We reviewed 246 patients who underwent splenectomy over a 16 year period. Indications for splenectomy were considered under the following headings: haematological (N = 116), trauma (N = 69), visceral carcinoma (N = 28), incidental (N = 13) and miscellaneous (N = 20). There were 28 deaths in the series, primarily among those in the intra-abdominal carcinoma (13) and multiple trauma (13) groups. Two deaths were recorded among patients undergoing elective splenectomy for benign disease. Thrombo-embolic complications were recorded in nine patients; respiratory tract infection in 36 patients and intra-abdominal abscess in two patients. Two cases of post-splenectomy pneumococcal septicaemia were documented, neither of which was fatal. While not an entirely benign procedure, splenectomy can be performed relatively safely, especially when performed for benign disease in an adult population.

Impaired proliferative responses of peripheral blood B cells from splenectomized subjects to phorbol ester and ionophore

The responses of peripheral blood B cells to mitogenic stimulation were examined in 12 splenectomized subjects without residual splenic function, as determined by pitted erythrocyte counts. These were compared to a group of healthy controls matched for age and sex. Polyclonal anti-immunoglobulin evoked a normal transient elevation in intracellular free Ca2+ in splenectomized subjects, thereby suggesting that the early events of the signal transduction pathway are not impaired. However, mitogenic stimulation by pre-treatment with phorbol ester and culture in presence of a calcium ionophore (Ionomycin) resulted in reduced uptake of 3H-thymidine and subsequent proliferation. Nevertheless, entry into the mitotic cycle, as assessed by expression of Ki67, was slightly, but not significantly impaired. Unlike in normal controls, where up to 7% of freshly-isolated B cells were Ki67+, almost no Ki67+ peripheral B cells were observed in splenectomized subjects. The data are consistent with the hypothesis that peripheral B cells in splenectomized subjects are in a reduced state of activation compared with normal controls and require additional growth factor stimulation before they can undergo mitosis.

Splenic autotransplantation and the immune system. Adequate testing required for evaluation of effect

The risk of severe infections after splenectomy, even after many years, is now well established. In attempts to prevent these infections, spleen-saving techniques, including autotransplantation of spleen fragments, have been performed, when possible in combination with vaccination. The problem in autotransplantation is the evaluation of functional activity. The results of the tests used until now often do not seem to correlate very well with the risk of developing an overwhelming postsplenectomy infection (OPSI). This may be related to the fact that the tests used evaluate general functions, and not specific spleen-related functions, such as the capacity to mount a primary response to certain polysaccharide antigens present in the capsule of bacteria known to cause OPSI. In this review, the significance of the spleen in the human immune system is discussed and the effects of splenectomy are described, including the precautions that can be taken to diminish the risk of postsplenectomy infections and sepsis. It appears that postsplenectomy vaccination is more successful when recently developed protein-conjugated polysaccharide vaccines are used. Because the present testing of the function of spleen autotransplants is not adequate, we suggest that new tests should be developed, employing appropriate polysaccharide antigens.

Pneumococcal septic arthritis after splenectomy in Felty's syndrome

A patient with Felty's syndrome who developed bilateral knee septic arthritis and septicaemia due to Streptococcus pneumoniae is described. She had had a previous splenectomy for symptomatic thrombocytopenia, having received pneumococcal vaccine before the operation. Measurement of antibody to the 23 vaccine serotypes showed protective concentrations before infection to just two. The infecting serotype was not represented in the vaccine, but a vigorous antibody response to this serotype occurred. The patient also developed glomerulonephritis due to immune complex deposition.

Postsplenectomy sepsis

This review examines the infectious consequences of elective and emergency splenectomy, highlighting the importance of infection with Streptococcus pneumoniae. The influence of splenectomy on the immune system is discussed and the efficacy of vaccines in preventing postsplenectomy sepsis is reviewed. The value of alternative methods of preventing postsplenectomy sepsis is considered.

Intradermal hepatitis B vaccine in thalassaemia and sickle cell disease

Thirty two patients with beta thalassaemia and sickle cell disease who were having regular blood transfusions were selected to test the efficacy and immunogenicity of low dose (2 micrograms or 0.1 ml) intradermal hepatitis B vaccine compared with the standard (20 micrograms or 1 ml) intramuscular dose. There was no significant difference in the rates of seroconversion, seroconversion had occurred in all patients by seven months. There were no significant differences in antibody titres between the intramuscular and intradermal groups at 1, 2, and 6 months. Although the titres were significantly higher in the intramuscular group at seven months and at 12-18 months, the antibody titre in the intradermal group did not fall below 10 IU/l. The results of this study suggest that low dose intradermal hepatitis B vaccination is an effective and economical way of stimulating an immune response in patients with beta thalassaemia and sickle cell disease.

Lymphocyte and complement abnormalities in splenectomized patients with hematologic disorders

Twenty-two patients, splenectomized 1 to 26 years earlier for hematologic disorders, were studied to determine possible defects in immunologic function or complement levels. Quantitation of B cells and T-cell subsets revealed slight decreases in the proportions of CD3 and CD4 cells but normal or increased absolute numbers of all cell populations. IgM synthesis in vitro by peripheral blood mononuclear cells was markedly diminished, but IgG synthesis was normal. Fractionation studies, in which various B-cell- and T-cell-enriched populations from controls and patients were combined, demonstrated diminished B-cell function in the patients. Sickle cell patients, who were functionally asplenic, showed similar deficits. Complement levels in splenectomized and sickle cell patients in both the classical and alternative pathways were generally normal. A modest decrease in component H in the alternative pathway in splenectomized and sickle cell patients probably was not clinically significant. In summary, splenectomized patients have a diminished capacity for IgM synthesis that can be attributed primarily to defective B-cell function. This may be partially responsible for their increased susceptibility to infection by encapsulated organisms.

Neutrophil chemotaxis in sickle cell anaemia, sickle cell beta zero thalassaemia, and after splenectomy

Neutrophil chemotaxis was evaluated in 28 patients with sickle cell anaemia, 10 patient with sickle cell beta zero thalassaemia, 25 patients who had undergone splenectomy, and 38 controls. The mean distance migrated by patients' neutrophils was not significantly different from that of neutrophils from controls. Although several immunological variables have been reported to be changed after loss of splenic function, we were unable to show a defect in neutrophil chemotaxis that could account for the increased susceptibility to infection.

Immunization with heat-killed pneumococci, but not pneumococcal capsular polysaccharides, improves survival in splenectomized mice

Immunization with pneumococcal capsular polysaccharides (pn PS) is advocated after splenectomy to decrease the risk of overwhelming sepsis. The clinical and experimental evidence for the benefit of immunization after splenectomy is controversial. Various reports in the literature have claimed a benefit of immunization after splenectomy, but careful review of methodologies reveals that heat-killed pneumococci (pn) were used to immunize the experimental animals. Since we have not been able to protect splenectomized (splx) mice by immunization with pn PS, we compared survival after live pneumococcal aerosol challenge and antibody (Ab) responses in splx and sham splx mice immunized with either pn PS or heat-killed pn. Immunization with either heat-killed type 3 pn or pn type 3 PS improved survival in sham-splx mice compared to saline controls (p less than 0.001). Only immunization with heat-killed type 3 pn improved survival in splx mice (p less than 0.001), while pn PS had no effect on survival compared to saline splx controls. Ab responses to pn type 3 PS measured by enzyme linked immunosorbent assay were depressed in splx mice compared to sham-splx mice regardless of the method of immunization. Sham-splx mice immunized with heat-killed pn had higher Ab levels compared to mice vaccinated with pn PS (p less than 0.001) suggesting an adjuvant effect in sham-splx mice. The data suggest that immunization with pn PS may not be beneficial to a splx host. Improved survival after immunization with heat-killed bacteria in splx mice may be related to Ab responses to antigens other than the capsular polysaccharide.

Impaired primary, but not secondary, immune response in breast cancer patients under adjuvant chemotherapy

The antibody response after vaccination against tick-borne encephalitis (TBE) was studied in patients with breast cancer. Although sex- and age-matched control persons produced high titers of anti-TBE antibodies 2 to 4 weeks after the second of two consecutive vaccinations, patients with breast cancer who were first vaccinated after the start of adjuvant chemotherapy consisting of cyclophosphamide, methotrexate and 5-fluorouracil (CMF) failed to do so. The lack of anti-TBE antibody production was found not only in patients under CMF chemotherapy, but also in those primarily vaccinated 6 to 12 months after the termination of CMF treatment. Patients with breast cancer who had been vaccinated either before or after the onset of disease, but before the initiation of chemotherapy, were shown to have developed significant anti-TBE antibody titers which persisted throughout the course of adjuvant treatment and could be boostered by revaccination during the course of CMF administration. The authors conclude that patients with breast cancer undergoing adjuvant chemotherapy experience a serious and prolonged defect in primary antibody production, whereas secondary immune responses remain unimpaired.

IgG and IgM antibody responses to pneumococcal vaccination in splenectomized children and in children who had non-operative management of splenic rupture

The IgG and IgM type specific anticapsular pneumococcal antibody titres were studied with ELISA during one year following vaccination with a 14-valent pneumococcal polysaccharide vaccine in four different patient groups: 41 children splenectomized after a traumatic rupture, 16 splenectomized because of disease, 15 non-surgically managed after splenic rupture, and 19 healthy controls. Serum samples were obtained before vaccination and after 14, 60, 180, and 360 days. The IgG antibody responses were equally good in all of the patient groups, while the IgM antibody responses were less pronounced in the splenectomized. In the non-surgically managed patients, the IgM antibody titres after vaccination, as well as antibody responses per se, were significantly higher for all 12 pneumococcal types studied than in the patients who were splenectomized. Both the IgG and the IgM antibody titres were highest at 14 days after vaccination. However, while the IgG titres for most pneumococcal types remained elevated at 360 days, the IgM titres soon fell to prevaccination levels. The antibody response was less good for the types 3 and 6 A. The results indicate that the IgG antibody response to pneumococcal polysaccharide vaccination is unaffected in splenectomized individuals, but the IgM antibody response is decreased. In patients with a healed traumatically damaged spleen, both the IgG and IgM responses seem to be normal.